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IP subnet calculator

Type an address with its prefix or mask to see the network, its usable range and masks. Split it into smaller subnets, or look up any prefix in the reference tables.

Network129.0.0.0/13
Usable hosts524,286
Subnet mask255.248.0.0
Addresses524,288
Network address
129.0.0.0
Broadcast address
129.7.255.255
First usable
129.0.0.1
Last usable
129.7.255.254
Usable hosts
524,286 (524,288 less the network and broadcast addresses)
Subnet mask
255.248.0.0
Wildcard mask
0.7.255.255 (Cisco ACLs, OSPF)
Prefix length
/13
Type
Public public
Old class
B (default /16)
As numbers
Hex 81000000 · Integer 2164260864 to 2164785151
Reverse DNS zones
0.129.in-addr.arpa
1.129.in-addr.arpa
2.129.in-addr.arpa
3.129.in-addr.arpa
4.129.in-addr.arpa
5.129.in-addr.arpa
6.129.in-addr.arpa
7.129.in-addr.arpa
/13 is not on a 8-bit boundary, so it takes 8 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10000001.00000000.00000000.00000000129.0.0.0
Subnet mask11111111.11111000.00000000.00000000255.248.0.0
Network10000001.00000000.00000000.00000000129.0.0.0
Broadcast10000001.00000111.11111111.11111111129.7.255.255
Split into smaller subnets/23
/14 (2)/15 (4)/16 (8)/17 (16)/18 (32)/19 (64)/20 (128)/21 (256)/22 (512)/23 (1,024)/24 (2,048)/25 (4,096)

129.0.0.0/13 makes 1,024 subnets of /23; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1129.0.0.0/23129.0.0.1 to 129.0.1.254129.0.1.255510
2129.0.2.0/23129.0.2.1 to 129.0.3.254129.0.3.255510
3129.0.4.0/23129.0.4.1 to 129.0.5.254129.0.5.255510
4129.0.6.0/23129.0.6.1 to 129.0.7.254129.0.7.255510
5129.0.8.0/23129.0.8.1 to 129.0.9.254129.0.9.255510
6129.0.10.0/23129.0.10.1 to 129.0.11.254129.0.11.255510
7129.0.12.0/23129.0.12.1 to 129.0.13.254129.0.13.255510
8129.0.14.0/23129.0.14.1 to 129.0.15.254129.0.15.255510
9129.0.16.0/23129.0.16.1 to 129.0.17.254129.0.17.255510
10129.0.18.0/23129.0.18.1 to 129.0.19.254129.0.19.255510
11129.0.20.0/23129.0.20.1 to 129.0.21.254129.0.21.255510
12129.0.22.0/23129.0.22.1 to 129.0.23.254129.0.23.255510
13129.0.24.0/23129.0.24.1 to 129.0.25.254129.0.25.255510
14129.0.26.0/23129.0.26.1 to 129.0.27.254129.0.27.255510
15129.0.28.0/23129.0.28.1 to 129.0.29.254129.0.29.255510
16129.0.30.0/23129.0.30.1 to 129.0.31.254129.0.31.255510
17129.0.32.0/23129.0.32.1 to 129.0.33.254129.0.33.255510
18129.0.34.0/23129.0.34.1 to 129.0.35.254129.0.35.255510
19129.0.36.0/23129.0.36.1 to 129.0.37.254129.0.37.255510
20129.0.38.0/23129.0.38.1 to 129.0.39.254129.0.39.255510
21129.0.40.0/23129.0.40.1 to 129.0.41.254129.0.41.255510
22129.0.42.0/23129.0.42.1 to 129.0.43.254129.0.43.255510
23129.0.44.0/23129.0.44.1 to 129.0.45.254129.0.45.255510
24129.0.46.0/23129.0.46.1 to 129.0.47.254129.0.47.255510
25129.0.48.0/23129.0.48.1 to 129.0.49.254129.0.49.255510
26129.0.50.0/23129.0.50.1 to 129.0.51.254129.0.51.255510
27129.0.52.0/23129.0.52.1 to 129.0.53.254129.0.53.255510
28129.0.54.0/23129.0.54.1 to 129.0.55.254129.0.55.255510
29129.0.56.0/23129.0.56.1 to 129.0.57.254129.0.57.255510
30129.0.58.0/23129.0.58.1 to 129.0.59.254129.0.59.255510
31129.0.60.0/23129.0.60.1 to 129.0.61.254129.0.61.255510
32129.0.62.0/23129.0.62.1 to 129.0.63.254129.0.63.255510
33129.0.64.0/23129.0.64.1 to 129.0.65.254129.0.65.255510
34129.0.66.0/23129.0.66.1 to 129.0.67.254129.0.67.255510
35129.0.68.0/23129.0.68.1 to 129.0.69.254129.0.69.255510
36129.0.70.0/23129.0.70.1 to 129.0.71.254129.0.71.255510
37129.0.72.0/23129.0.72.1 to 129.0.73.254129.0.73.255510
38129.0.74.0/23129.0.74.1 to 129.0.75.254129.0.75.255510
39129.0.76.0/23129.0.76.1 to 129.0.77.254129.0.77.255510
40129.0.78.0/23129.0.78.1 to 129.0.79.254129.0.79.255510
41129.0.80.0/23129.0.80.1 to 129.0.81.254129.0.81.255510
42129.0.82.0/23129.0.82.1 to 129.0.83.254129.0.83.255510
43129.0.84.0/23129.0.84.1 to 129.0.85.254129.0.85.255510
44129.0.86.0/23129.0.86.1 to 129.0.87.254129.0.87.255510
45129.0.88.0/23129.0.88.1 to 129.0.89.254129.0.89.255510
46129.0.90.0/23129.0.90.1 to 129.0.91.254129.0.91.255510
47129.0.92.0/23129.0.92.1 to 129.0.93.254129.0.93.255510
48129.0.94.0/23129.0.94.1 to 129.0.95.254129.0.95.255510
49129.0.96.0/23129.0.96.1 to 129.0.97.254129.0.97.255510
50129.0.98.0/23129.0.98.1 to 129.0.99.254129.0.99.255510
51129.0.100.0/23129.0.100.1 to 129.0.101.254129.0.101.255510
52129.0.102.0/23129.0.102.1 to 129.0.103.254129.0.103.255510
53129.0.104.0/23129.0.104.1 to 129.0.105.254129.0.105.255510
54129.0.106.0/23129.0.106.1 to 129.0.107.254129.0.107.255510
55129.0.108.0/23129.0.108.1 to 129.0.109.254129.0.109.255510
56129.0.110.0/23129.0.110.1 to 129.0.111.254129.0.111.255510
57129.0.112.0/23129.0.112.1 to 129.0.113.254129.0.113.255510
58129.0.114.0/23129.0.114.1 to 129.0.115.254129.0.115.255510
59129.0.116.0/23129.0.116.1 to 129.0.117.254129.0.117.255510
60129.0.118.0/23129.0.118.1 to 129.0.119.254129.0.119.255510
61129.0.120.0/23129.0.120.1 to 129.0.121.254129.0.121.255510
62129.0.122.0/23129.0.122.1 to 129.0.123.254129.0.123.255510
63129.0.124.0/23129.0.124.1 to 129.0.125.254129.0.125.255510
64129.0.126.0/23129.0.126.1 to 129.0.127.254129.0.127.255510
65129.0.128.0/23129.0.128.1 to 129.0.129.254129.0.129.255510
66129.0.130.0/23129.0.130.1 to 129.0.131.254129.0.131.255510
67129.0.132.0/23129.0.132.1 to 129.0.133.254129.0.133.255510
68129.0.134.0/23129.0.134.1 to 129.0.135.254129.0.135.255510
69129.0.136.0/23129.0.136.1 to 129.0.137.254129.0.137.255510
70129.0.138.0/23129.0.138.1 to 129.0.139.254129.0.139.255510
71129.0.140.0/23129.0.140.1 to 129.0.141.254129.0.141.255510
72129.0.142.0/23129.0.142.1 to 129.0.143.254129.0.143.255510
73129.0.144.0/23129.0.144.1 to 129.0.145.254129.0.145.255510
74129.0.146.0/23129.0.146.1 to 129.0.147.254129.0.147.255510
75129.0.148.0/23129.0.148.1 to 129.0.149.254129.0.149.255510
76129.0.150.0/23129.0.150.1 to 129.0.151.254129.0.151.255510
77129.0.152.0/23129.0.152.1 to 129.0.153.254129.0.153.255510
78129.0.154.0/23129.0.154.1 to 129.0.155.254129.0.155.255510
79129.0.156.0/23129.0.156.1 to 129.0.157.254129.0.157.255510
80129.0.158.0/23129.0.158.1 to 129.0.159.254129.0.159.255510
81129.0.160.0/23129.0.160.1 to 129.0.161.254129.0.161.255510
82129.0.162.0/23129.0.162.1 to 129.0.163.254129.0.163.255510
83129.0.164.0/23129.0.164.1 to 129.0.165.254129.0.165.255510
84129.0.166.0/23129.0.166.1 to 129.0.167.254129.0.167.255510
85129.0.168.0/23129.0.168.1 to 129.0.169.254129.0.169.255510
86129.0.170.0/23129.0.170.1 to 129.0.171.254129.0.171.255510
87129.0.172.0/23129.0.172.1 to 129.0.173.254129.0.173.255510
88129.0.174.0/23129.0.174.1 to 129.0.175.254129.0.175.255510
89129.0.176.0/23129.0.176.1 to 129.0.177.254129.0.177.255510
90129.0.178.0/23129.0.178.1 to 129.0.179.254129.0.179.255510
91129.0.180.0/23129.0.180.1 to 129.0.181.254129.0.181.255510
92129.0.182.0/23129.0.182.1 to 129.0.183.254129.0.183.255510
93129.0.184.0/23129.0.184.1 to 129.0.185.254129.0.185.255510
94129.0.186.0/23129.0.186.1 to 129.0.187.254129.0.187.255510
95129.0.188.0/23129.0.188.1 to 129.0.189.254129.0.189.255510
96129.0.190.0/23129.0.190.1 to 129.0.191.254129.0.191.255510
97129.0.192.0/23129.0.192.1 to 129.0.193.254129.0.193.255510
98129.0.194.0/23129.0.194.1 to 129.0.195.254129.0.195.255510
99129.0.196.0/23129.0.196.1 to 129.0.197.254129.0.197.255510
100129.0.198.0/23129.0.198.1 to 129.0.199.254129.0.199.255510
101129.0.200.0/23129.0.200.1 to 129.0.201.254129.0.201.255510
102129.0.202.0/23129.0.202.1 to 129.0.203.254129.0.203.255510
103129.0.204.0/23129.0.204.1 to 129.0.205.254129.0.205.255510
104129.0.206.0/23129.0.206.1 to 129.0.207.254129.0.207.255510
105129.0.208.0/23129.0.208.1 to 129.0.209.254129.0.209.255510
106129.0.210.0/23129.0.210.1 to 129.0.211.254129.0.211.255510
107129.0.212.0/23129.0.212.1 to 129.0.213.254129.0.213.255510
108129.0.214.0/23129.0.214.1 to 129.0.215.254129.0.215.255510
109129.0.216.0/23129.0.216.1 to 129.0.217.254129.0.217.255510
110129.0.218.0/23129.0.218.1 to 129.0.219.254129.0.219.255510
111129.0.220.0/23129.0.220.1 to 129.0.221.254129.0.221.255510
112129.0.222.0/23129.0.222.1 to 129.0.223.254129.0.223.255510
113129.0.224.0/23129.0.224.1 to 129.0.225.254129.0.225.255510
114129.0.226.0/23129.0.226.1 to 129.0.227.254129.0.227.255510
115129.0.228.0/23129.0.228.1 to 129.0.229.254129.0.229.255510
116129.0.230.0/23129.0.230.1 to 129.0.231.254129.0.231.255510
117129.0.232.0/23129.0.232.1 to 129.0.233.254129.0.233.255510
118129.0.234.0/23129.0.234.1 to 129.0.235.254129.0.235.255510
119129.0.236.0/23129.0.236.1 to 129.0.237.254129.0.237.255510
120129.0.238.0/23129.0.238.1 to 129.0.239.254129.0.239.255510
121129.0.240.0/23129.0.240.1 to 129.0.241.254129.0.241.255510
122129.0.242.0/23129.0.242.1 to 129.0.243.254129.0.243.255510
123129.0.244.0/23129.0.244.1 to 129.0.245.254129.0.245.255510
124129.0.246.0/23129.0.246.1 to 129.0.247.254129.0.247.255510
125129.0.248.0/23129.0.248.1 to 129.0.249.254129.0.249.255510
126129.0.250.0/23129.0.250.1 to 129.0.251.254129.0.251.255510
127129.0.252.0/23129.0.252.1 to 129.0.253.254129.0.253.255510
128129.0.254.0/23129.0.254.1 to 129.0.255.254129.0.255.255510
129129.1.0.0/23129.1.0.1 to 129.1.1.254129.1.1.255510
130129.1.2.0/23129.1.2.1 to 129.1.3.254129.1.3.255510
131129.1.4.0/23129.1.4.1 to 129.1.5.254129.1.5.255510
132129.1.6.0/23129.1.6.1 to 129.1.7.254129.1.7.255510
133129.1.8.0/23129.1.8.1 to 129.1.9.254129.1.9.255510
134129.1.10.0/23129.1.10.1 to 129.1.11.254129.1.11.255510
135129.1.12.0/23129.1.12.1 to 129.1.13.254129.1.13.255510
136129.1.14.0/23129.1.14.1 to 129.1.15.254129.1.15.255510
137129.1.16.0/23129.1.16.1 to 129.1.17.254129.1.17.255510
138129.1.18.0/23129.1.18.1 to 129.1.19.254129.1.19.255510
139129.1.20.0/23129.1.20.1 to 129.1.21.254129.1.21.255510
140129.1.22.0/23129.1.22.1 to 129.1.23.254129.1.23.255510
141129.1.24.0/23129.1.24.1 to 129.1.25.254129.1.25.255510
142129.1.26.0/23129.1.26.1 to 129.1.27.254129.1.27.255510
143129.1.28.0/23129.1.28.1 to 129.1.29.254129.1.29.255510
144129.1.30.0/23129.1.30.1 to 129.1.31.254129.1.31.255510
145129.1.32.0/23129.1.32.1 to 129.1.33.254129.1.33.255510
146129.1.34.0/23129.1.34.1 to 129.1.35.254129.1.35.255510
147129.1.36.0/23129.1.36.1 to 129.1.37.254129.1.37.255510
148129.1.38.0/23129.1.38.1 to 129.1.39.254129.1.39.255510
149129.1.40.0/23129.1.40.1 to 129.1.41.254129.1.41.255510
150129.1.42.0/23129.1.42.1 to 129.1.43.254129.1.43.255510
151129.1.44.0/23129.1.44.1 to 129.1.45.254129.1.45.255510
152129.1.46.0/23129.1.46.1 to 129.1.47.254129.1.47.255510
153129.1.48.0/23129.1.48.1 to 129.1.49.254129.1.49.255510
154129.1.50.0/23129.1.50.1 to 129.1.51.254129.1.51.255510
155129.1.52.0/23129.1.52.1 to 129.1.53.254129.1.53.255510
156129.1.54.0/23129.1.54.1 to 129.1.55.254129.1.55.255510
157129.1.56.0/23129.1.56.1 to 129.1.57.254129.1.57.255510
158129.1.58.0/23129.1.58.1 to 129.1.59.254129.1.59.255510
159129.1.60.0/23129.1.60.1 to 129.1.61.254129.1.61.255510
160129.1.62.0/23129.1.62.1 to 129.1.63.254129.1.63.255510
161129.1.64.0/23129.1.64.1 to 129.1.65.254129.1.65.255510
162129.1.66.0/23129.1.66.1 to 129.1.67.254129.1.67.255510
163129.1.68.0/23129.1.68.1 to 129.1.69.254129.1.69.255510
164129.1.70.0/23129.1.70.1 to 129.1.71.254129.1.71.255510
165129.1.72.0/23129.1.72.1 to 129.1.73.254129.1.73.255510
166129.1.74.0/23129.1.74.1 to 129.1.75.254129.1.75.255510
167129.1.76.0/23129.1.76.1 to 129.1.77.254129.1.77.255510
168129.1.78.0/23129.1.78.1 to 129.1.79.254129.1.79.255510
169129.1.80.0/23129.1.80.1 to 129.1.81.254129.1.81.255510
170129.1.82.0/23129.1.82.1 to 129.1.83.254129.1.83.255510
171129.1.84.0/23129.1.84.1 to 129.1.85.254129.1.85.255510
172129.1.86.0/23129.1.86.1 to 129.1.87.254129.1.87.255510
173129.1.88.0/23129.1.88.1 to 129.1.89.254129.1.89.255510
174129.1.90.0/23129.1.90.1 to 129.1.91.254129.1.91.255510
175129.1.92.0/23129.1.92.1 to 129.1.93.254129.1.93.255510
176129.1.94.0/23129.1.94.1 to 129.1.95.254129.1.95.255510
177129.1.96.0/23129.1.96.1 to 129.1.97.254129.1.97.255510
178129.1.98.0/23129.1.98.1 to 129.1.99.254129.1.99.255510
179129.1.100.0/23129.1.100.1 to 129.1.101.254129.1.101.255510
180129.1.102.0/23129.1.102.1 to 129.1.103.254129.1.103.255510
181129.1.104.0/23129.1.104.1 to 129.1.105.254129.1.105.255510
182129.1.106.0/23129.1.106.1 to 129.1.107.254129.1.107.255510
183129.1.108.0/23129.1.108.1 to 129.1.109.254129.1.109.255510
184129.1.110.0/23129.1.110.1 to 129.1.111.254129.1.111.255510
185129.1.112.0/23129.1.112.1 to 129.1.113.254129.1.113.255510
186129.1.114.0/23129.1.114.1 to 129.1.115.254129.1.115.255510
187129.1.116.0/23129.1.116.1 to 129.1.117.254129.1.117.255510
188129.1.118.0/23129.1.118.1 to 129.1.119.254129.1.119.255510
189129.1.120.0/23129.1.120.1 to 129.1.121.254129.1.121.255510
190129.1.122.0/23129.1.122.1 to 129.1.123.254129.1.123.255510
191129.1.124.0/23129.1.124.1 to 129.1.125.254129.1.125.255510
192129.1.126.0/23129.1.126.1 to 129.1.127.254129.1.127.255510
193129.1.128.0/23129.1.128.1 to 129.1.129.254129.1.129.255510
194129.1.130.0/23129.1.130.1 to 129.1.131.254129.1.131.255510
195129.1.132.0/23129.1.132.1 to 129.1.133.254129.1.133.255510
196129.1.134.0/23129.1.134.1 to 129.1.135.254129.1.135.255510
197129.1.136.0/23129.1.136.1 to 129.1.137.254129.1.137.255510
198129.1.138.0/23129.1.138.1 to 129.1.139.254129.1.139.255510
199129.1.140.0/23129.1.140.1 to 129.1.141.254129.1.141.255510
200129.1.142.0/23129.1.142.1 to 129.1.143.254129.1.143.255510
201129.1.144.0/23129.1.144.1 to 129.1.145.254129.1.145.255510
202129.1.146.0/23129.1.146.1 to 129.1.147.254129.1.147.255510
203129.1.148.0/23129.1.148.1 to 129.1.149.254129.1.149.255510
204129.1.150.0/23129.1.150.1 to 129.1.151.254129.1.151.255510
205129.1.152.0/23129.1.152.1 to 129.1.153.254129.1.153.255510
206129.1.154.0/23129.1.154.1 to 129.1.155.254129.1.155.255510
207129.1.156.0/23129.1.156.1 to 129.1.157.254129.1.157.255510
208129.1.158.0/23129.1.158.1 to 129.1.159.254129.1.159.255510
209129.1.160.0/23129.1.160.1 to 129.1.161.254129.1.161.255510
210129.1.162.0/23129.1.162.1 to 129.1.163.254129.1.163.255510
211129.1.164.0/23129.1.164.1 to 129.1.165.254129.1.165.255510
212129.1.166.0/23129.1.166.1 to 129.1.167.254129.1.167.255510
213129.1.168.0/23129.1.168.1 to 129.1.169.254129.1.169.255510
214129.1.170.0/23129.1.170.1 to 129.1.171.254129.1.171.255510
215129.1.172.0/23129.1.172.1 to 129.1.173.254129.1.173.255510
216129.1.174.0/23129.1.174.1 to 129.1.175.254129.1.175.255510
217129.1.176.0/23129.1.176.1 to 129.1.177.254129.1.177.255510
218129.1.178.0/23129.1.178.1 to 129.1.179.254129.1.179.255510
219129.1.180.0/23129.1.180.1 to 129.1.181.254129.1.181.255510
220129.1.182.0/23129.1.182.1 to 129.1.183.254129.1.183.255510
221129.1.184.0/23129.1.184.1 to 129.1.185.254129.1.185.255510
222129.1.186.0/23129.1.186.1 to 129.1.187.254129.1.187.255510
223129.1.188.0/23129.1.188.1 to 129.1.189.254129.1.189.255510
224129.1.190.0/23129.1.190.1 to 129.1.191.254129.1.191.255510
225129.1.192.0/23129.1.192.1 to 129.1.193.254129.1.193.255510
226129.1.194.0/23129.1.194.1 to 129.1.195.254129.1.195.255510
227129.1.196.0/23129.1.196.1 to 129.1.197.254129.1.197.255510
228129.1.198.0/23129.1.198.1 to 129.1.199.254129.1.199.255510
229129.1.200.0/23129.1.200.1 to 129.1.201.254129.1.201.255510
230129.1.202.0/23129.1.202.1 to 129.1.203.254129.1.203.255510
231129.1.204.0/23129.1.204.1 to 129.1.205.254129.1.205.255510
232129.1.206.0/23129.1.206.1 to 129.1.207.254129.1.207.255510
233129.1.208.0/23129.1.208.1 to 129.1.209.254129.1.209.255510
234129.1.210.0/23129.1.210.1 to 129.1.211.254129.1.211.255510
235129.1.212.0/23129.1.212.1 to 129.1.213.254129.1.213.255510
236129.1.214.0/23129.1.214.1 to 129.1.215.254129.1.215.255510
237129.1.216.0/23129.1.216.1 to 129.1.217.254129.1.217.255510
238129.1.218.0/23129.1.218.1 to 129.1.219.254129.1.219.255510
239129.1.220.0/23129.1.220.1 to 129.1.221.254129.1.221.255510
240129.1.222.0/23129.1.222.1 to 129.1.223.254129.1.223.255510
241129.1.224.0/23129.1.224.1 to 129.1.225.254129.1.225.255510
242129.1.226.0/23129.1.226.1 to 129.1.227.254129.1.227.255510
243129.1.228.0/23129.1.228.1 to 129.1.229.254129.1.229.255510
244129.1.230.0/23129.1.230.1 to 129.1.231.254129.1.231.255510
245129.1.232.0/23129.1.232.1 to 129.1.233.254129.1.233.255510
246129.1.234.0/23129.1.234.1 to 129.1.235.254129.1.235.255510
247129.1.236.0/23129.1.236.1 to 129.1.237.254129.1.237.255510
248129.1.238.0/23129.1.238.1 to 129.1.239.254129.1.239.255510
249129.1.240.0/23129.1.240.1 to 129.1.241.254129.1.241.255510
250129.1.242.0/23129.1.242.1 to 129.1.243.254129.1.243.255510
251129.1.244.0/23129.1.244.1 to 129.1.245.254129.1.245.255510
252129.1.246.0/23129.1.246.1 to 129.1.247.254129.1.247.255510
253129.1.248.0/23129.1.248.1 to 129.1.249.254129.1.249.255510
254129.1.250.0/23129.1.250.1 to 129.1.251.254129.1.251.255510
255129.1.252.0/23129.1.252.1 to 129.1.253.254129.1.253.255510
256129.1.254.0/23129.1.254.1 to 129.1.255.254129.1.255.255510

IPv4 CIDR reference (/0 to /32)

IPv4 prefix lengths
PrefixSubnet maskWildcardAddressesUsable hostsSizeTypical use
/00.0.0.0255.255.255.2554,294,967,2964,294,967,29416,777,216 × /24
/1128.0.0.0127.255.255.2552,147,483,6482,147,483,6468,388,608 × /24
/2192.0.0.063.255.255.2551,073,741,8241,073,741,8224,194,304 × /24
/3224.0.0.031.255.255.255536,870,912536,870,9102,097,152 × /24
/4240.0.0.015.255.255.255268,435,456268,435,4541,048,576 × /24
/5248.0.0.07.255.255.255134,217,728134,217,726524,288 × /24
/6252.0.0.03.255.255.25567,108,86467,108,862262,144 × /24
/7254.0.0.01.255.255.25533,554,43233,554,430131,072 × /24
/8255.0.0.00.255.255.25516,777,21616,777,21465,536 × /24Old class A; 10.0.0.0/8
/9255.128.0.00.127.255.2558,388,6088,388,60632,768 × /24
/10255.192.0.00.63.255.2554,194,3044,194,30216,384 × /24
/11255.224.0.00.31.255.2552,097,1522,097,1508,192 × /24
/12255.240.0.00.15.255.2551,048,5761,048,5744,096 × /24172.16.0.0/12
/13255.248.0.00.7.255.255524,288524,2862,048 × /24
/14255.252.0.00.3.255.255262,144262,1421,024 × /24
/15255.254.0.00.1.255.255131,072131,070512 × /24
/16255.255.0.00.0.255.25565,53665,534256 × /24Old class B; 192.168.0.0/16
/17255.255.128.00.0.127.25532,76832,766128 × /24
/18255.255.192.00.0.63.25516,38416,38264 × /24
/19255.255.224.00.0.31.2558,1928,19032 × /24
/20255.255.240.00.0.15.2554,0964,09416 × /24
/21255.255.248.00.0.7.2552,0482,0468 × /24
/22255.255.252.00.0.3.2551,0241,0224 × /24Large office or guest Wi-Fi (1,022 hosts)
/23255.255.254.00.0.1.2555125102 × /24Larger office LAN (510 hosts)
/24255.255.255.00.0.0.2552562541 × /24Typical office LAN (old class C)
/25255.255.255.1280.0.0.1271281261/2 of a /24Smaller LAN or VLAN
/26255.255.255.1920.0.0.6364621/4 of a /24Smaller LAN or VLAN
/27255.255.255.2240.0.0.3132301/8 of a /24Small VLAN, phones, cameras
/28255.255.255.2400.0.0.1516141/16 of a /24Small VLAN, phones, cameras
/29255.255.255.2480.0.0.7861/32 of a /24Small fixed public block (5 usable)
/30255.255.255.2520.0.0.3421/64 of a /24Point-to-point (old style)
/31255.255.255.2540.0.0.1221/128 of a /24Point-to-point link (RFC 3021)
/32255.255.255.2550.0.0.0111/256 of a /24One host

IPv6 prefix reference

IPv6 prefix lengths
PrefixAddresses/64 LANs/48 sitesNibbleTypical use
/342,535,295,865,117,307,932,921,825,928,971,026,432 (2^125)2,305,843,009,213,693,95235,184,372,088,832NoAll global unicast (2000::/3)
/165,192,296,858,534,827,628,530,496,329,220,096 (2^112)281,474,976,710,6564,294,967,296Yes
/20324,518,553,658,426,726,783,156,020,576,256 (2^108)17,592,186,044,416268,435,456YesLarge provider allocation (RIPE minimum for some)
/29633,825,300,114,114,700,748,351,602,688 (2^99)34,359,738,368524,288NoRIPE allocation to a provider (often)
/3279,228,162,514,264,337,593,543,950,336 (2^96)4,294,967,29665,536YesProvider allocation (RIPE default)
/364,951,760,157,141,521,099,596,496,896 (2^92)268,435,4564,096Yes
/40309,485,009,821,345,068,724,781,056 (2^88)16,777,216256Yes
/4419,342,813,113,834,066,795,298,816 (2^84)1,048,57616Yes
/481,208,925,819,614,629,174,706,176 (2^80)65,5361YesOne site or organisation (RIPE PI / assignment)
/5275,557,863,725,914,323,419,136 (2^76)4,096Yes
/564,722,366,482,869,645,213,696 (2^72)256YesSmall site or home (common provider assignment)
/60295,147,905,179,352,825,856 (2^68)16YesSome home broadband (16 LANs)
/6418,446,744,073,709,551,616 (2^64)1YesOne LAN or VLAN (needed for SLAAC)
/7272,057,594,037,927,936 (2^56)1/256 of a /64Yes
/80281,474,976,710,656 (2^48)1/65,536 of a /64Yes
/964,294,967,2961/4,294,967,296 of a /64YesEmbeds an IPv4 address (NAT64)
/11265,5361/281,474,976,710,656 of a /64Yes
/1202561/72,057,594,037,927,936 of a /64Yes
/124161/1,152,921,504,606,846,976 of a /64Yes
/12641/4,611,686,018,427,387,904 of a /64No
/12721/9,223,372,036,854,775,808 of a /64NoPoint-to-point link (RFC 6164)
/12811/18,446,744,073,709,551,616 of a /64YesOne host or loopback

Private and special ranges

IPv4

Special-purpose ranges
RangeNameWhat it is
255.255.255.255/32Limited broadcastEvery host on the local network
0.0.0.0/8This networkNot routed; 0.0.0.0 means "any address" in settings
10.0.0.0/8Private (RFC 1918)Office and home networks; not routed on the internet
100.64.0.0/10Shared address space (CGNAT)Used by providers behind carrier-grade NAT (RFC 6598)
127.0.0.0/8LoopbackThis computer
169.254.0.0/16Link-local (APIPA)Self-assigned when no DHCP server answers
172.16.0.0/12Private (RFC 1918)Office and home networks; not routed on the internet
192.0.0.0/24IETF protocol assignmentsSpecial uses such as DS-Lite
192.0.2.0/24Documentation (TEST-NET-1)For examples; never used on a network
192.88.99.0/246to4 relay (deprecated)Formerly anycast for 6to4
192.168.0.0/16Private (RFC 1918)Office and home networks; not routed on the internet
198.18.0.0/15BenchmarkingNetwork equipment testing (RFC 2544)
198.51.100.0/24Documentation (TEST-NET-2)For examples; never used on a network
203.0.113.0/24Documentation (TEST-NET-3)For examples; never used on a network
224.0.0.0/4MulticastOne-to-many traffic, such as IPTV and routing protocols
240.0.0.0/4ReservedFuture use; not usable on most systems

IPv6

Special-purpose ranges
RangeNameWhat it is
::/128UnspecifiedNo address; :: means "any address" in settings
::1/128LoopbackThis computer
::ffff:0:0/96IPv4-mappedAn IPv4 address written as IPv6
64:ff9b::/96NAT64IPv4 addresses reached through a NAT64 gateway
100::/64Discard onlyTraffic sent here is dropped (RFC 6666)
2001:db8::/32DocumentationFor examples; never used on a network
2001::/32TeredoIPv6 tunnelled over IPv4 UDP
2002::/166to4IPv6 tunnelled over IPv4 (largely retired)
3fff::/20DocumentationFor examples (RFC 9637)
fc00::/7Unique local (ULA)Private IPv6, like RFC 1918; usually fd00::/8
fe80::/10Link-localEvery IPv6 interface has one; not routed
ff00::/8MulticastOne-to-many traffic; replaces broadcast
2000::/3Global unicastPublic internet addresses

About this tool

A network is written as an address and a prefix length, such as 192.168.1.0/24: the first 24 bits name the network and the rest number the devices on it. The calculator works out where the network starts and ends, how many devices it holds, its subnet and wildcard masks, and the reverse DNS zone to ask your provider for.

It also splits a network into equal smaller ones (one per VLAN or site), turns a range of addresses into the fewest CIDR blocks for a firewall rule, and lists every IPv4 prefix length and the common IPv6 ones in reference tables.

Common questions

Why are two addresses lost in every IPv4 subnet?

The first address names the network and the last is the broadcast address, so a /24 has 256 addresses but 254 for devices. A /31 (a link between two routers) and a /32 (one host) are the exceptions.

What size of IPv6 network should a LAN use?

Always /64. Devices pick their own address within it (SLAAC), which needs the full 64 bits. A site usually gets a /48 or /56 from its provider, which holds 65,536 or 256 LANs.

What is a wildcard mask?

The subnet mask turned inside out: 255.255.255.0 becomes 0.0.0.255. Cisco access lists and OSPF use it to say which bits must match.

Which ranges can I use inside an office?

IPv4: 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16. IPv6: unique local addresses from fd00::/8, though most networks use the public prefix from their provider.